In recent years, improvements have been made in the early discovery and diagnosis accuracy of lesioned portions by endoscopy. Moreover, a variety of treatment tools for use in an endoscope have been developed. As a result, even greater levels of performance are anticipated from endoscopes. However, image data for a body cavity interior which is captured by a conventional endoscope is transmitted by wire using an image transmission cable (referred to below as a ‘cable’) to a display apparatus set up at a location separated from the endoscope. Because of this, the positional relationships between a user, a test subject, and the display apparatus are limited by the cable.
Therefore, for example, in Japanese Unexamined Patent Application, First Publication No. H6-335450, an endoscope has been proposed in which image data captured by an endoscope is transmitted by wireless to a display apparatus. In this endoscope, there are no limits on the positional relationships between the user, the test subject, and the display apparatus, and neither are there any hindrances to the operation of the endoscope by the user.
Furthermore, in order to improve the early discovery and diagnosis accuracy of lesioned portions, further increases in image quality are sought in static image data which is photographed using an endoscope. As a consequence, there is a demand for static image data photographed by an endoscope to be either uncompressed data, or lossless compressed data in which absolutely no data loss is caused by the expansion processing, or lossy compressed data in which only slight data loss is caused by the expansion processing.
Furthermore, in moving image data, because the image frames are continuously updated, there is very little obvious deterioration in image quality. In contrast, in static image data in which the image frames are not updated, because the deterioration in image quality is obvious when a comparison with the same image frame is made, there is a demand for the quality of static image data to be higher than that of moving image data.